Liquid heat-transmission system



I My 31,1927. v 1,630,956

D. M. LUEHRS LIQUID mm TRANSMISSION SYSTEM Filed Oct. 6, 1924 2 Sheets-Sheet -1 1,630,956 M y 1927- n. M. LUEHRS LIQUID HEAT TRAfiSlll-SS'ION- :SYSTEM Filed Oct. 6. 1.924 I 2 Shasta-Sheet 2 been opened that the pump will-operate to app renew Lewes sta -res PATENT attics.

ANI L M- .IJUEHM or c EvnLe D, OHIO.

I.|IQ J'IZD HEAT-TRANglVlISSION SYSTEM.

Application filedflctober This invention relates to improvements in means for distributing heat to heat-utilising apparatus through the IIIQCl'lllIILOf ,h gh flash mineral oil, which is heated toa highdegree' and pumped through distributing pipes as described in my co-pcnding application Se rial Number 700,205; tiled li larch =19, 1924:. The present improvements relate vmore particularly to means for increasing the pressure oftheoil, in the individual heat-utilizingdevices, above the normal pressure in the .distributing pipes when the oil in the coils of the individual heat-utilizing device has been chilled and has become viscous and sluggishin its movement. as when said devicehlas which is to beheated. "l he invention also relates to means for controllingthe quantity of Oll'Cll'ClllZtllQCl through the hetli'rlltlllZlng. apparatus to control, the -,temperature therein.

In carrying outthe invention, lprovlde in the branch pipes which extend from the main distributing i pipes. to each heat-utilizing apparatus, a pump for forcing theoil through the .coilsor jacket, of the apparatus,

and a thermostaticdevice, in one :tornro'f the invention controls the o aeration .otthe pump, and 1 1n another form. controls a bypass valve fl or shunt-mg more or less .oflthe oil around the pump. It the. oil in the. coils or jacket of filliIlCllVlClllZLl heat-utilizing. apparatus is chilled, the arrangement/ is such apressure to the oil above that existing in the distributing pipes and thus the apparatus will heat more quicklyt-han itonly affected by v the pressure in the distributing pipes. nAtter the apparatus has become heated, the thermostatic controlling device willcause the; individual pump to vary thesupply ot'oil so as to maintain the desired temperature in the apparatus. I

In the accompanying drawing,

-Fig1 1 diagrammatic view illustrating my invention in connection with a motor opera'ted pump, in which the speed of the'motor is controlled by a thermostatic device in the heat-utilizing apparatus;

Fig. 2 is a vertical section throi'ighla-baking oven showing a pump for forcing the oil through the heating coils of. the oven, and a by-p'ass valve, thermostatically controlled, tor regulating the amount of oil passed through the coils;

and filledwith .cold material.

6, 1924. Serial No. 742,0 6.

r 1g. 3 is an enlarged sectional view ,through the by-pass valve; and,

Fig. i is a section through a part of the oven wall, showing the thermostatic device which controls the flow ofair for operating the bypass valve. i i i j Referring to Fig. 1 of the drawing, a represents a'pipe through which hot oil is forced from a suitable heater, as illustrated in my co-pending application above mentioned, and 73 represents the return pipe of the'distributing system. Connected at various points along the distributing pipes" are. heat-,utilizing devices 0, whichmay lie-baking ovens provided with heating coils or j ack etedvessels, or apparatus otany ,kind where heat isrequired. A jpipe Lle ads. to eacliheatutilizing device through. apump 2, which, asshown in Fig 1, is preferably a rotary pump connected. to ,an electric motor .3. From thepump 2, .a pipe extendslinto the jacket or coils in ,the heat-utilizing device and returns-through branch pipe l to the main return pipe' b of the system. A 's uit- ,able thermostatic device .(Z is arranged in t pp Pa t:e h,heetrntil e. ppa Htus, andin Fig. 1,,thi-s thermostatic device operates the arm 5 ofa rheostat 1%, connected in the armature circuit of the motor. In

th dr w n 6 an epre n the su 7 wires of an electric power system andithe ,motors which operatethe pumps associated with the heat-utilizing apparatus are connected topthese supply :wires through conductors Sand 9, respectively, amt through manually operable switchesv 10. I

i In the operation of the apparatus shown in Fig. 1, the switch, being closed andlthe oven or other heatutilizing apparatus being cool, the rheostat arm. will .occupythe position shownand the motor will operate and cause ,jthe pumpto. force the hot'oil, at a pressure above the normal pressure, in the distributing pipes, through the coils of the ,heatutilizing. apparatus. This will cause the oil to circulate'treely and thus the apparatus Vwill'heat quickly. 'When the temperature in the apparatus reaches th'edesired degree, the thermostatic device will-gradually move the rheostat arm to the left andinsert resistance in the motorcircuit, which will slow down the motor and thereby ,cause the pump to force less oil through the apparatus. It the temperature in the apparatus falls, thethermostatwill cause the rheostat arm to move in the opposite direction and increase the speed of the motor and the pump will then deliver oil at a faster rate to the apparatus, causing the temperature therein to' rise. After the contents and walls of' the heat-utilining apparatus become heated to the desired de 'ree, the rheostat arm will be held in a balanced position which will cause the motor to run at a constant speed and the pump will deliver a constant quantity of oil, to keep the contents of the apparatus at a constant temperature.

in Fig. 2, I have shown an apparatus suitable for use with a pump which is driven pipe 13 to the coils let within the chamber 15, and returns through pipe 16 to the return pipe 5 of the distributing system.

' by-pass connection 17 is arranged between the pressure side of the pump and the intake pipe 12 and this connection is controlled by a valve 18, which is operable by a diaphragm 19 to open and close the by-pas's and also to open and close the passageway from the pump to the pipe 18. The diaphragm 19 is contained within a chamber 20, and a valve stem 21 connects the diaphragm with the valve. A spring 22, coiled around the valve stem, normally presses the diaphragm out wardly, as shown in Fig. 3, and holds the valve 18 against theseat 23, thereby cutting off the flow of oil from the pump to the pipe 13 and heating coil 14%. hen the diaphragm is pressed to the left, in the manner hereinafter described, the valve opens the passageway for the flow of oil from the pump to the heating coil, and in the extreme left hand position of the valve, the latter fits against the seat 24 and closes the end of theby-pass connection 17 so that no oil can be by-passed around the pump. In the intermediate position of the valve, the flow of oil will be divided between the bypass connection and the pipe 13 leading to the heating coil.

For operating the valve. I provide a pipe 25, leadingfrom a suitable source of compressed air to the chamber 20, and when air is admitted to this pipe, the diaphragm and valve will be forced to the left, in Fig. 3,

and when the air is released from the pipe the diaphragm and valve will return to the positions shown in said figure. The flow of air from the air-compressing apparatus or reservoir through the pipe 25 is controlled by a valve 6, which is operated by a thermostat d, and a vent opening 26 is arranged in the pipe 25 between the valve 6 and the casing 20. The purpose of this vent opening is to permit the air to leak slowly out of the is low the oil in the coil loses heat rapidly and becomes more viscous than the oil in the distributing pipes. The pump associated with the apparatus forces the viscous oil through the coil more rapidly than the oil would flow with only the pressure in the distributing pipes, and hence the chamber and its contents will heat rapidly. When thetemperature in the chamber reaches a predetermined degree, the thermostatic valve will operate to gradually close the valve 6 and cut off the supply of compressed air from the chamber 20. Assuming the valve 6 to be completely closed, the air pressure in the pipe 25, leading to the back of the diaphragm, will be relieved by leakage at the vent 26 and the spring 22 will then'cause the valve '18 to close the connection to the heating coil and leave the bypass connection wide open. The thermostatic valve operates gradually and in the practical use of the apparatus, when the contents of the chamber become heated to the desired degree, this valve will permit a sufiicient air pressure to be maintained in the pipe 25 to cause the diaphragm valve to assume a stationary intermediate position in which a part of the hot oil will flow through the coils of the heating chamber and part will pass through the bypass connection. This, of course, is assuming that the temperature required in the'heating chamber is considerably lower than the temperature of the oil in the distributing pipes.

It will be evident that if the temperature in the main distributing pipe falls or rises, the controlling apparatus described will compensatefor this rise or fall in temperature, and the speed of the motor. in Fig. 1, and'the setting of the bypass valve in Fig. 2, will be automatically adjusted according to such variations in temperature of the oil in the distributing system.

What I claim is: V i 1. The combination with the supply and return pipes of a hot oil distributing system, of aheat-utilizing apparatus, a branch pipe connecting said apparatus'withjthe supply and return pipes, and a pump connected in said branch pipe for forcing the oil through the latter.

2. The combination with the supply and return pipes of a hot oil distributing system, 01 a heat utilizing apparatus, a branch pipe connecting said apparatus with the supply and return pipes and a pump connected in said branch pipe and adapted to force oil therethrongh, and means controlled by the temperature in the apparatus for regulating the quantity of oil circulated through the apparatus by the pump.

3. The combination with the supply and return pipes of a hot oil distributing system, of a heat utilizing apparatus, connected to said pipes, a pump associated With the ap paratus and adapted to force oil therethrough, a by-pass connection around the pump, a valve for controlling the flow of oil through the apparatus and the by-pass connection, and means controlled by the temperature in said apparatus for adjusting the position of said valve.

at. The combination with the supply and return pipes of a hot oil distributing system, of a heat-utilizing apparatus, connected to said pipes, a pump associated With the apparatus and adapted to force oil therethrough, a by-pass connection around the pump, a valve for controlling the flow of oil through the apparatus and the bypass connection,a device operable by fluid pressure for actuating said valve, a pipe for conveying fluid under pressure to said device, a

through the apparatus and the by-pass cona nection, said valve being normally in position to bypass the oil, pneumatically operated means for moving said valve in the direction to close the by-pass connection, and a thermally operated device associated With the apparatus for controlling said means.

In testimony whereof I hereunto atfix my signature.

DANIEL M. LUEH-RS. 

